1. Field of the Invention
The invention relates generally to voltage regulation of an integrated circuit. More particularly, embodiments of the invention relate to communication between an integrated circuit and a voltage regulator providing a supply voltage to the integrated circuit.
2. Background Art
In various computing platforms, an integrated circuit (IC) such as a central processing unit (CPU) will receive power provided by a voltage regulator (VR). The VR may variously provide power to the IC, for example by variously providing different current outputs at a first supply voltage level. The VR may further provide to the IC various other current outputs at a second supply voltage level different from the first supply voltage level.
Typically, the VR determines the providing of power to the IC based on an indication of a particular power need of the IC. For example, a VR may receive a signal from the IC indicating that the IC needs less (or more) power, for example, and/or that the IC needs to enter a mode of operation better suited for a particular level or range of power consumption. In response to the received signal, the VR may allocate more or less voltage regulation resources to the providing of a supply voltage to the IC. For example, the VR may allocate a set of phases of the VR, where each of the allocated phases contributes current to the total current output of the VR.
In allocating voltage regulation resources, the VR may allocate resources which are rated for different optimal levels of power output. Therefore, at any given time, the VR may be operating at greater or lesser level of power efficiency, depending on the particular selection of voltage resources dedicated to provide an output current. Also, at any given time, the VR may be operating at a particular load level—e.g. a particular power load and/or a particular thermal load—which limits the capacity of the VR to accommodate additional power requirements of the IC. Unfortunately, the level of efficiency of the VR at any given time and/or the existing load of the VR may be unrelated to whether increased data processing is being demanded of the IC. As a result, the IC may respond to increased processing demands by requesting the VR to allocate a particular combination of voltage regulation resources which is less efficient or beyond an operating capacity of the VR.